conspire
     v 1: engage in plotting or enter into a conspiracy, swear
          together; "They conspired to overthrow the government"
          [syn: {cabal}, {complot}, {conjure}, {machinate}]
     2: act in unison or agreement and in secret towards a deceitful
        or illegal purpose; "The two companies conspired to cause
        the value of the stock to fall" [syn: {collude}]
Source: WordNet® 2.0